— 
~~ 
NOTES ON SCIENTIFIC RESEARCH. 121 
The distillation-water runs off through the bent neck. When the distillation is 
finished the cock is closed and the oil is brought up into the graduated neck by filling 
up the contents from the distillate. The percentage-proportion of oil of the plant or 
drug is readily calculable from the volume of oil read off. 
A possible source of error lies in the solubility of the oil in water, but this factor 
may usually be disregarded; in other cases it is possible to estimate the solubility 
approximately once for all and to take it into account in making the calculation. 
The author specially recommends his apparatus for the estimation of the oil-content 
of sandalwood, ajowan, cloves, 8c. To which we may add that, although the apparatus 
may be very useful for some purposes, it is certainly unsuitable for the estimation of 
clove oil, because this oil is heavier than water and cannot be introduced into the 
neck of the flask offhand. 
The observations made by W. H. Simmons?) on the citronellol-content of geranium 
oil have induced other chemists to make similar investigations. From an article on 
this subject which has appeared in an English periodical”) we take the following 
abstracts: In the determination of citronellol by formylation®) it is immaterial whether 
the geranium oil is first saponified or not; the formic acid, therefore, acts upon esterified 
geraniol equally destructively as upon free geraniol. With geranium oil of different 
origin, acetylation on the one hand and formylation on the other, gave the following 
figures for the total geraniol and the citronellol contents: — 
Total geraniol Citronellol Total geraniol Citronellol 
eee 2 = . - 72,7 Jo 39,8 %o Gorsican va) 207357. 20 45,9 °/o 
miserian . . 74,1 °%/o 32,9 °/o ASiank fee 2h TZ S To 51,0 °/o 
Bourbon . . 73,0 %o 4A3 %/o Beane MIT AS EO MTHONG 62,3 Jo 
In like manner citronellol determinations were carried out with samples of rose 
oil, the result being as follows: — 
Total geraniol Citronellol 
% Bulgarian Rose oil. . . 70,1 to 75,0 %o 30,1 to 36,7 °/o 
French 5 Nn a i HE 65,0 °/o 33,1 °/o 
BUA. 2. 60,/ and /3;0°/0° 39,2 and 26,2°/0 
Persian "i pb ce haa ile 38,6 °/o 34,5 °/o 
The behaviour of the last-named sample is quite abnormal, and it also differs from 
the others in its solidification point, which was decidedly higher, viz. 29 to 30°). 
In the case of three samples of adulterated Bulgarian rose oil the citronellol content 
varied from 13,5 to 22,8 p.c. 
It was again found that formylation does not completely destroy the geraniol, but 
that a small proportion of it is esterified, and that in the case of freshly-prepared 
citronellol especially the results obtained are often excessive, up to 119,8 p.c. being 
recorded in one instance?). 
L. V. Redman, A.J. Weith and F. E. P. Brock*) have lately tested a method for the 
quantitative estimation of phenols, including thymol, proposed some time ago by 
J. M. Wilkie”). This method is based upon the same principle as that recommended 
*) Comp. Report October 1913, 63. — %) Perfum. Record 4 (1913), 328. — %) Gildemeister and Hoffmann, 
The Volatile Oils, 294Ed. Vol.1, p. 580. — *) The purity of this oil is probably somewhat doubtful. — 
*) Perfum. Record 5 (1914), 51. — %) Journ. ind. eng. Chemistry 6 (1913), 831. — 7%) Journ. Soc. chem. 
Industry 30 (1911), 398. 
